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Vocabulary list Definitions

Chapter 1-4 Earth’s moon

Pages 30-33

1) Highlands Mountain ranges on the moon
2) Maria Lowland plains on the moon - caused by volcanoes and moonquakes
3) Rilles Valleys on the moon (Trick- both rilles and valleys have two ll's)
4) Perigee When the moon is closest to Earth in its orbit (pretty close)
5) Apogee When the moon is farthest to Earth in its orbit (away)
6) Hadley Rille One of the largest valleys on the moon
7) Moon’s Period of Rotation 27.3 days - same as its revolution
8) Moon’s Period of Revolution 27.3 days - same as its rotation
9) Neil Armstrong 1st person to walk on the moon (1969)
10) Buzz Aldrin 2nd person to walk on the moon (1969)
11) Galileo Galilei


1st person to view the moon through a telescope (1609)


Answer on Index cards:
12) Compare the moon’s gravity   to Earth’s gravity.  

Gravity is Earth’s gravity – Objects weigh much less on the moon.  Objects on Earth are six times heavier than on the moon.


13) How did scientists figure out the distance from Earth to the moon?  

Scientists left a mirror on the moon to help them calculate the distance from Earth to the moon. They knew how fast light travels (the speed of light), they bounced a beam of light from earth to the moon and timed how long it took to get back


14) Describe three theories of how the moon was created.

(textbook pg. 118 and 119)


1) The moon formed millions or billions of kilometers away and was later captured by Earth’s gravity.

2) The moon formed from the same cloud of gas and dust that the Sun, Earth and the rest of our solar system formed from. The moon rocks lend support to this theory.  Big Bang Theory

*3) A giant asteroid (the size of Mars) hit the Earth and tore a chunk out of Earth’s surface. The Chunk is now our moon (stayed in orbit due to Earth’s Gravity.) The hole that was left on Earth is now the Pacific Ocean. This is also supported by moon rocks.



15) How might the moon’s craters and rilles have formed?
It is believed that they formed by either volcanic activity or moonquakes. The craters have volcanic rock in them which supports the theory that volcanoes were responsible.  Moonquakes would also cause volcanic eruptions and they could explain the long valleys, Rilles, on the moon.